Week 16 System Integration

This week, I focused on integrating all the hardware and software components of my final project. It was both challenging and rewarding to see everything come together into a functional system. Through debugging and testing, I gained a deeper understanding of how each part interacts within the whole.

assignment:

• Design and document the system integration for your final project.

1.1 System Overview

The Honor Tree consists of multiple components working together:

• Input: Hall sensors detect 3D-printed apples with embedded magnets.
• Output: WS2812B LEDs light up and DFPlayer Mini plays a celebration sound.

• Controller: A XIAO-ESP32-C3 serves as the central microcontroller.

• Structure: A multi-layer tree made from laser-cut cardboard and a felt board holds the electronics.

1.2 Bill of Materials

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Component	Quantity	Unit Price (RMB)	Notes
PLA Filament	93g	--	Provided by FabLab Formshop
3mm Corrugated Cardboard	3 pcs	--	Laser-cut tree structure
9mm Felt Board	1	21.8	Tree background
Seeed XIAO-ESP32-C3	1	34.05	Main microcontroller
WS2812B RGB LEDs	8 pcs	17.36	Light up apples
A3144 Hall Sensor	8 pcs	17.6	Detect magnetic apples
Neodymium Magnets	8 pcs	3.3	Inside 3D-printed apples
DFPlayer Mini	1	39	Plays sound effects
Speaker (3W 8Ω)	1	4.12	Connected to DFPlayer
SD Card (8GB)	1	3.7	Stores MP3 files

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⚙️ Circuit and Electronics Integration

I designed a custom PCB using EasyEDA based on the XIAO ESP32-C3 pinout:

• Pins D0–D5 are connected to Hall sensors and WS2812B LEDs.
• D6 and D7 are connected to DFPlayer Mini.
• Power pins and right-angle headers are used for neat wiring.

💡 RGB + Button Combo

I embedded WS2812B LEDs inside the 3D-printed apple holders. They light up when the correct apple is placed on the tree.

🧱 Structure Integration

The tree is made of laser-cut cardboard layers and a felt board. The electronic components are mounted behind the board using 3D-printed supports.

• Cutouts allow sensors and LEDs to align with apples.
• The speaker is embedded inside a 2D laser-cut cardboard music box.
• A cutout is reserved for the USB charging cable on the back of the felt board.

🧪 System Test & Result

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1.3 Circuit and Electronics Integration

I designed a custom PCB using EasyEDA based on the XIAO ESP32-C3,A total of 8 pins are required for the Hall sensors and 1 for the LED, plus two pins for the mini player, along with power and ground pins. No additional pin expansion board is needed for the Xiao.

PCB board

• Pins D0–D5 & D8-D10 are connected to Hall sensors and WS2812B LEDs.
• D6 and D7 are connected to DFPlayer Mini.

Overall circuit layout diagram

1.4 Magnetic Switch

A 3D-printed apple contains an embedded magnet. When the magnet approaches the Hall sensor, the corresponding WS2812B LED lights up.

🧱 Structure Integration

Cutouts for the LED lights, Hall sensor, and the 3D-printed apple support.

• Cutouts allow sensors and LEDs to align with apples.

• The speaker is embedded inside a 2D laser-cut cardboard music box.

• A cutout is left for hanging the 3D apple, allowing the magnet to trigger the Hall sensor.

1.5 System Test & Result

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When a student attaches their apple:

1. The Hall sensor detects it.
2. The matching LED lights up.
3. A “Great job!” message plays from the speaker.

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This provides immediate feedback and motivates students through interactive celebration.

✅ Reflection

Integrating all the parts was challenging yet rewarding. Aligning structure and electronics required multiple iterations. The result is a beautiful and meaningful classroom interaction tool that helps students feel recognized and proud of their efforts.

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This provides immediate feedback and motivates students through interactive celebration.

✅ Reflection

Integrating all the parts was challenging yet rewarding. Aligning structure and electronics required multiple iterations. The result is a beautiful and meaningful classroom interaction tool that helps students feel recognized and proud of their efforts.